Taiwanese Hokkien (/ˈhɒkiɛn/ HOK-ee-en, US also /ˈhoʊkiɛn/ HOH-kee-en), or Taiwanese (Chinese: 臺灣話; Pe̍h-ōe-jī: Tâi-oân-ōe), also known as Taigi (臺語; Tâi-gí), Taiwanese Taigi (臺灣台語; Tâi-oân Tâi-gí; Tâi-uân Tâi-gí), Taiwanese Southern Min (臺灣閩南語; Tâi-oân Bân-lâm-gí), Hoklo and Holo, is a variety of the Hokkien language spoken natively by more than 70 percent of the population of Taiwan. It is spoken by a significant portion of those Taiwanese people who are descended from Hoklo immigrants of southern Fujian. It is one of the national languages of Taiwan.

Taiwanese is generally similar to Hokkien spoken in Xiamen (Amoy), Quanzhou, and Zhangzhou, as well as dialects used in Southeast Asia, such as Singaporean Hokkien, Penang Hokkien, Philippine Hokkien, Medan Hokkien, and Southern Peninsular Malaysian Hokkien. It is mutually intelligible with the Amoy and Zhangzhou varieties at the mouth of the Jiulong River in China, and with Philippine Hokkien to the south in the Philippines, spoken altogether by about 3 million people. The mass popularity of Hokkien entertainment media from Taiwan has given prominence to the Taiwanese variety of Hokkien, especially since the 1980s.

Taiwanese Hokkien is a variety of Hokkien, a Southern Min language. Like many varieties of Min Chinese, it has distinct literary and colloquial layers of vocabulary, often associated with formal and informal registers respectively. The literary layer can be traced to the late Tang dynasty, and as such is related to Middle Chinese. In contrast, the colloquial layers of Min varieties are believed to have branched from the mainstream of Chinese around the time of the Han dynasty.

Regional variations within the Taiwanese variant may be traced back to Hokkien variants spoken in Southern Fujian, specifically those from Quanzhou and Zhangzhou, and later from Amoy. Taiwanese also contains loanwords from Japanese and native Formosan languages. Recent work by scholars such as Ekki Lu, Toru Sakai, and Li Khin-hoann, based on former research by scholars such as Ong Iok-tek, has gone so far as to associate part of the basic vocabulary of the colloquial Taiwanese with the Austronesian and Tai language families; however, such claims are controversial.

The literary form of Hokkien once flourished in Fujian and was brought to Taiwan by early emigrants. Tale of the Lychee Mirror, a manuscript of a series of plays published during the Ming dynasty in 1566, is one of the earliest known works. This form of language is now largely extinct. However, literary readings of the numbers are used in certain contexts, such as reciting telephone numbers (see Literary and colloquial readings of Chinese characters).^{[citation needed]}

During the Yuan dynasty, Quanzhou became a major international port for trade with the outside world. From that period onwards, many people from the Hokkien-speaking regions (southern Fujian) started to emigrate overseas due to political and economic reasons. One of the destinations for the emigrants was the island of Taiwan (formerly Formosa), starting around 1600. They brought their native Hokkien language with them.

During the late Ming dynasty, the political chaos pushed more migrants from southern Fujian and eastern Guangdong to Taiwan. The earliest immigrants involved in Taiwan's development included pirate-merchants Pedro Yan Shiqi and Zheng Zhilong. In 1621, Chinese Peter and his forces, hailing from Zhangzhou, occupied Ponkan (modern-day Beigang, Yunlin) and started to develop Tirosen (modern-day Chiayi). After the death of Peter and another pirate, Li Dan of Quanzhou, Zheng sought to dominate the Strait of Taiwan. By 1628, he had grown so powerful that the Ming court bestowed him the official title, "Patrolling Admiral".

In 1624, the number of Chinese on the island was about 25,000. During the reign of Chongzhen Emperor (1627–1644), there were frequent droughts in the Fujian region. Zheng and a Chinese official suggested sending victims to Taiwan and provide "for each person three taels of silver and for each three people one ox". Although this plan was never carried out, the Zheng family maintained an interest in Taiwan that would have dire consequences for the Dutch Empire, who ruled Taiwan as Dutch Formosa at the time.